Green’s Dictionary of Slang

(W.I.) a shebeen, an illegal drinking club or a party where drink is sold without a licence; also attrib.; also as v.

1977		D. Powis Signs of Crime 174: Blues An illegal drinking house (shebeen), especially one where amplified dance music is also provided.
1980		M. Thelwell Harder They Come 203: He [...] went to blues dances where highly amplified black-American music dominated.
1986		R. Hewitt White Talk Black Talk 63: If they go to a blues – it’s their music, it’s packed, the atmosphere and all that.
1999		Indep. on Sun. Real Life 11 July 5: She was out most of the time at blues parties with men.
2001		K. Sampson Outlaws (ms.) 78: I weren’t sure where this particular blues was going down.
2008		A. Wheatle Dirty South 198: I used to sneak out to clubs, raves and go bluesing.
2011		(con. 1970s) Observer Music 30 Jan. 🌐 Black Britain, like Jamaica, preferred to keep up to speed with the latest releases via the ‘sound system’ (disco) and the ‘blues dance’ (a house party with pay bar). ‘A blues was the only place you could get a girl,’ says Bovell.